Note 10 - Stock Option Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Beginning balance (in shares)	4,101,000
Beginning balance (in dollars per share)	$ 18.72
Granted (in shares)	2,442,000
Granted (in dollars per share)	$ 14.69
Exercised (in shares)	(577,559)	(516,552)
Exercised (in dollars per share)	$ 7.25
Forfeitures (in shares)	(560,000)
Forfeitures (in dollars per share)	$ 21.53
Expired (in shares)	(375,000)
Expired (in dollars per share)	$ 24.10
Ending balance (in shares)	5,030,000	4,101,000
Ending balance (in dollars per share)	$ 17.37	$ 18.72
Ending balance	5 years 36 days
Ending balance	$ 3,728
Expected to vest (in shares)	3,104,000
Expected to vest (in dollars per share)	$ 16.42
Expected to vest	6 years 80 days
Expected to vest	$ 714
Exercisable (in shares)	1,857,000
Exercisable (in dollars per share)	$ 18.98
Exercisable	3 years 69 days
Exercisable	$ 2,999